Kate Middleton Kicked Off Coronation Weekend in a Royal Blue Cocktail Dress With an Unexpected Leg Slit

The coronation festivities have officially begun — and all eyes are on Kate Middleton and her fashion (sorry, King Charles). Earlier today, the Princess of Wales attended a luncheon in a sophisticated summer-ready white mididress with black piping before switching into a royal blue evening dress.

Middleton and her husband Prince William attended a Friday evening reception at Buckingham Palace, during which she wore a tea-length indigo-colored cocktail dress from Self-Portrait, which had a crisscrossing high-neck (with a very slight keyhole cutout), power shoulders with silver buttons, a ruched draping midsection, and a leg slit.

The princess accessorized the long-sleeved frock with some royal jewels, of course. Diamond-and-sapphire drop earrings that had belonged to the Queen Mother hung from her ears while her hair was styled in a super-deep side part that swept across her forehead before cascading into big glamorous curls. For his part, Prince William matched his wife in a navy suit with a matching patterned tie.

Throughout the party, Kate mingled with the guests including Mary, Crown Princess of Denmark, and Crown Prince Frederik of Denmark, as well as first lady Dr. Jill Biden and her granddaughter,  Finnegan Biden.

Earlier this week, British Fashion Council member Josh Birch Jones told Page Six that we could expect to see Middleton in more "modernized" looks this weekend along with family gemstones from the archives.

“All eyes will be focused on the Princess of Wales, who will inevitably attract attention with her classic, yet personal style approach,” Birch Jones said. “Kate’s new title holds much responsibility, meaning that her participation during the coronation will be heavily watched, so a statement look is called for.”

“Jewelry will also play a prominent role for the coronation, therefore I predict we may see Kate turn to the royal jewelry collection for this event,” he continued before adding that we could see the princess “possibly wearing pieces in honor of the late Princess Diana or Queen Elizabeth, despite often opting for more casual jewelry options from brands such as Zara.”